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Jun 25, 2019, 05:06 PM
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Perhaps it helps more with the signal pattern, giving a more even coverage wherever the receiver (model) is relative to the transmitter?
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Jun 26, 2019, 12:57 AM
Ardupilot Lead Testing
Marco67's Avatar
Quote:
Originally Posted by BrumBob
Perhaps it helps more with the signal pattern, giving a more even coverage wherever the receiver (model) is relative to the transmitter?
Unfortunately this is not the case, although theoretically it should be, which is why I'm asking for explanations.
In any normal system the double antenna helps, it doesn't get worse.
Is an IXJT module that behaves like in my video defective?
If the external antenna should provide better signal coverage, you should know that this is not the case.
On a quad with Ardupilot I logged the RSSI, as well as seeing it on the Horus, and the data corresponds.
Here by connecting the external antenna I've a signal drop of over 15%, when perhaps it should be the other way around.
Those of Fr-Sky should give us explanations.
They are lucky that I bought this used radio, if it was new I would have immediately returned it, posting a bad review on my social channels.
In the Horus X10 there is another IXJT with four antennas predispositions, and only two are connected, the one above and one internal, and it would be interesting if someone did the same tests even on the tx one.
Jun 26, 2019, 01:23 AM
Ardupilot Lead Testing
Marco67's Avatar
Quote:
Originally Posted by RGS2010
Marco...I appreciate your tenacity in trying to figure this out. I'm watching with interest to see what the answers are. I have wondered the same. I thought the ability to add an extra antenna would, OF COURSE (I thought), help with diversity and/or signal strength...but alas...??????????????
Maybe he does, but it would be interesting to understand how.
Fr-Sky has the misfortune that in Open-TX you can see many things that are hidden in their firmware, so some behaviors of the internal components are immediately highlighted.
Is that why they push to use their firmware?
An internal antenna, regardless of how it was made, will never be better than an external omnidirectional, since it is known that any component near it will somehow shield the signal output.
So an external antenna should help, not get worse.
Jun 26, 2019, 01:43 AM
Happy FPV flyer
Kilrah's Avatar
Except the external antenna starts at a loss becasue of the extra connector.
Jun 26, 2019, 02:05 AM
Carbo (-nator) ;-)
Quote:
Originally Posted by Marco67
An internal antenna, regardless of how it was made, will never be better than an external omnidirectional, since it is known that any component near it will somehow shield the signal output.
Can you give some numbers? Here are mine.
Bear in mind, that early S6R showed to high RSSI numbers, 10dB less are the expected values with recent RX.
Jun 26, 2019, 03:38 AM
Ardupilot Lead Testing
Marco67's Avatar
Quote:
Originally Posted by Allerhopp
Can you give some numbers? Here are mine.
Bear in mind, that early S6R showed to high RSSI numbers, 10dB less are the expected values with recent RX.
I calibrated better the external antenna, tested with X8R updated to the latest INT firmware:
X9D Plus S.E.: RSSI 56
Horus X12S internal antenna: RSSI 54
Horus X12S internal+external antenna: RSSI 55

Wow, 1 RSSI point in addition, a record!
Last edited by Marco67; Jun 26, 2019 at 06:23 AM.
Jun 26, 2019, 07:36 AM
Always Fly 2 Mistakes High!
RGS2010's Avatar
Quote:
Originally Posted by Marco67
I calibrated better the external antenna, tested with X8R updated to the latest INT firmware:
X9D Plus S.E.: RSSI 56
Horus X12S internal antenna: RSSI 54
Horus X12S internal+external antenna: RSSI 55

Wow, 1 RSSI point in addition, a record!
I'm AT LEAST glad that the X12 has relatively the same RSSI numbers with its internal antenna as my trusty X9D+ has with the external.
Jun 26, 2019, 07:47 AM
Carbo (-nator) ;-)
Quote:
Originally Posted by Marco67
I calibrated better the external antenna, tested with X8R updated to the latest INT firmware:
X9D Plus S.E.: RSSI 56
Horus X12S internal antenna: RSSI 54
Horus X12S internal+external antenna: RSSI 55

Wow, 1 RSSI point in addition, a record!
Why do you complain? This are perfect numbers.
Jun 26, 2019, 10:30 AM
Ardupilot Lead Testing
Marco67's Avatar
I did other tests, swapping the internal cables on the IXJT, so that the connector for the internal antenna was the SMA and the external one therefore became the internal one, in this way I was able to test as primary some omnidirectional antennas.
With all I've had worse results than the internal dipole of the Horus, which at this point I must admit work well because it has no connector between cable and antenna, which creates dispersion.
But I noticed that the polarization is very selective, I show it in the image, from 54 to 61.
So most likely I will make myself a dopile that I will connect to the internal EXT connector of the IXJT module, leaving everything inside the radio.
However I still don't understand how the IXJT module work with the two antennas.
Jun 26, 2019, 11:31 AM
Happy FPV flyer
Kilrah's Avatar
AFAIK it just switches antenna after every packet sent.
Jun 26, 2019, 11:48 AM
Ardupilot Lead Testing
Marco67's Avatar
Quote:
Originally Posted by Kilrah
AFAIK it just switches antenna after every packet sent.
Probable, but the RSSI and RAS displayed are relative only to the external one, that's why "I've the feeling that it falls", of course, shows the external one.
Jun 26, 2019, 12:13 PM
Registered User
3djc's Avatar
RSSI is measured by the receiver, that doesn’t know or care which antenna is sending the signal. RAS on the other end comes from the module
Jun 26, 2019, 12:28 PM
Ardupilot Lead Testing
Marco67's Avatar
You're right, but the RAS is related to the external.
So it remains to understand why here it either falls or remains the same, only Fr-Sky knows how the module reasons.
Jun 26, 2019, 12:42 PM
AKA 8178 - MIke Dailey
Jet_Flyer's Avatar
Originally before September 2016 or around that time the internal and external antennas were selected individually and each provided a separate SWR number. The internal antenna was added to the external antenna in a time share mode around the September time frame and most likely the SWR source remained the external antenna.

Mike
Jun 26, 2019, 01:50 PM
Ardupilot Lead Testing
Marco67's Avatar
Therefore finding a IXJT firmware prior to that date could be tested separately.
Unfortunately the old firmware have been removed from their site, and in any case I don't think that Open-TX 2.2.3 would digest this "separate mode".


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